Political collapses are usually triggered by a single event - a corruption scandal, a horrific gaffe, the emergence of a lovechild, for example. But the demise of Joe Biden has been a slow rolling disaster, something painful for many to watch. Everyone in the Democrat party loves Mr Biden, and many Republicans like him too. But the majority appears to have concluded that he is not the right man to be president. On paper, Mr Biden was the ideal candidate. Barack Obama"s vice president for eight years. Beloved among African-American voters in the southern states. A child of the "Rust Belt," born in Scranton, Pennsylvania. A hero to "blue collar" voters, many of whom switched to Donald Trump in 2016. It was Mr Biden who the Republican US president least wanted to face, fearing he could take back struggling industrial states like Pennsylvania, Ohio, Michigan and Wisconsin. Even before he entered the race national polls had Mr Biden as the clear front-runner for the Democrat nomination. Head-to-head polls showed him beating Mr Trump easily in a general election. On April 25 last year, Mr Biden finally announced, but a series of lackluster debate performances followed. Given his status in the party Mr Biden seemed genuinely surprised and aggrieved that younger rivals would question his record on issues including race relations, and voting for the Iraq war. He had no effective responses. His answers seemed rambling. Among several gaffes he told America to go to his website "Joe30330" when he meant text "Joe30330". In one of his most baffling answers he said parents should use record players to teach their children. "Social workers help parents deal with how to raise their children. It’s not that they don’t want to help, they don’t know what to play the radio, make sure the television...excuse me, make sure you have the record player on at night, the...make sure that kids hear words, a kid coming from a very poor school...a very poor background will hear four million words fewer spoken by the time we get there." Asked about how he would tackle sexual violence against women, Mr Biden said: "We have to just change the culture, period, and keep punching at it, and punching at it, and punching at it. It will be a big [groans in the audience]...no, I really mean it. It’s a gigantic issue." In another embarrassing moment, he offended black voters by saying: "Poor kids are just as bright, and just as talented, as white kids." On one occasion Mr Biden looked directly into TV cameras and said: "I want to be clear, I’m not going nuts." When he was vice president Mr Biden"s gaffes and word salads received fleeting attention. But in the age of social media they were replayed endlessly. His campaign team tried to play it safe. His public appearances were more sparse than rivals. In stump speeches he spoke in vague terms about how he already knew world leaders, "wouldn"t need on-the-job-training."and was the "most electable" candidate. But there were few concrete policy proposals about how to take the country forward. Mr Biden regularly declined to take questions from journalists and voters. When he did, there were mishaps. In Iowa he grabbed a voter who asked about climate change by the lapels and told him to vote for someone else. The man, who had been going to vote for Mr Biden, said he was "disturbed" by how the former vice president "pushed and poked" him. Moving on to New Hampshire, Mr Biden took a question from student Madison Moore, 21, about why he had done so badly in Iowa. He responded: "You’re a lying, dog-faced pony soldier." His campaign hurriedly clarified that it was a joke, and a line from a John Wayne movie. But the damage was done. Miss Moore said: "It was kind of humiliating to be called a liar on national TV by the former vice president..." Meanwhile, a 2017 video re-emerged of Mr Biden speaking at a swimming pool where he had worked as a life guard in his youth. Mr Biden said: "And by the way, you know, I sit on the stand, and it’d get hot. I gotta lotta, I got hairy legs, that turn, that, that, turn, uh, blond in the sun. And the kids used to come up and reach into the pool and rub my leg down so it was straight, and then watch the hair come back up again. So I learned about roaches. I learned about kids jumping on my lap. And I’ve loved kids jumping on my lap." Mr Biden"s campaign has also been beset by a lack of money. Despite his long connections with donors he was significantly outraised by Bernie Sanders and Pete Buttigieg. His campaign sent out desperate emails and texts to supporters pleading for funds. Even then, despite all the setbacks, Mr Biden remained ahead in an average national polls. A month ago he was still eight points clear of Mr Sanders. But after his fourth place finish in Iowa, which Mr Biden called a "gut punch," Mr Sanders overtook him in national polls. When Mr Biden came in fifth in New Hampshire, Mr Sanders opened up a five point lead nationally. Mr Biden is now putting all his efforts into South Carolina, where he still leads. The state votes on Feb 29. But one of his advisers told Politico: "This is horrendous. We’re all scared." America loves a comeback story, and Mr Biden still hopes African-American voters in South Carolina will stand by him. But, even if he wins there, the reprieve may be short-lived.